powerful, and plainly insuperable, and as it were mere fate and necessity. And yet Telesius does not even attempt to refer this virtue to heat and cold. And rightly so; for it is a thing which neither conflagration, nor torpor and congelation, can add anything to or detract anything from or have any power over, while itself meantime is active both in the sun and at the centre of the earth, and everywhere else. But his mistake appears to have lain here-that while he acknowledges a certain and definite mass of matter, he is blind to the virtue by which that matter keeps itself undiminished in quantity, and (buried in the deepest darkness of the Peripatetics) ranks this as an accessory; whereas it is the very principal, vibrating one body, removing another, solid and adamantine in itself, and the fountain whence emanate the decrees of possible and impossible with inviolable authority. The common school philosophy likewise childishly attempts to grasp it in a set of words; thinking it enough to set it down as a rule that there cannot be two bodies in the same place; but the virtue and the process thereof it never contemplates with its eyes open, nor dissects to the quick; little knowing how much depends on it, and what a light may thence rise to the sciences. But (to return to the present business) this virtue, however great it be, falls beyond the principles of Telesius. I must now

pass on to that virtue which is as the converse of the former, namely, that which maintains the connexion of matter. For as matter refuses to be overpowered by matter, so does matter refuse to be separated from matter. Notwithstanding there is great doubt whether this law of nature be as peremptory as the other. For Telesius maintained, and so did Democritus, the existence of a collective vacuum without any limit, in order that individual beings may lay aside and sometimes even forşake the one contiguous to them, with difficulty (as they say) and against their will, that is, when subdued and forced by some greater violence; and this he tries to prove by certain experiments, especially adducing those which are everywhere cited for the contradiction and refutation of a vacuum, and as it were making extracts from them, and amplifying them so as to allow beings to be under some slight necessity of holding to that which is contiguous, but so that if they be more strongly pressed, they will admit a vacuum; as we see in water-clocks, in which if the hole through which the water runs is too small,

they will want an air-hole to enable the water to descend; but if the hole be larger, even though there be no air-hole, the water, pressing with a heavier weight on the hole, flows downwards, not caring for the vacuum above. In like manner, in bellows, if you shut them and then stop the mouth so that there is no passage for the air to enter, and then raise and expand them, if the leather be thin and weak it bursts; if it be thick and not liable to burst it holds; and so in other things. But these experiments are neither exactly proved nor do they altogether satisfy the inquiry or settle the question; and though by them Telesius thinks that he is applying himself to things and inventions, and endeavours to distinguish more accurately what has been observed confusedly by others, yet he is no way equal to the work, nor does he unravel the matter to the end, but falls off in the middle, -a habit common both to him and the Peripatetics; who are very owls in looking at experiments; and that not so much from weakness of vision, as because it is clouded by opinions, as by cataracts, and from impatience of full and fixed consideration. But this question (one of the most difficult) as to how far a vacuum is allowed, and at what distances seeds may attract or repel each other, and what there is in this matter peremptory and invariable, I refer to the place where I shall treat of a vacuum. For it is not of much importance to the present question whether Nature utterly abhors a vacuum, or whether beings (as Telesius thinks it more correct to say) delight in mutual contact. For I make it plain, that this, whether it be abhorrence of vacuum or desire of contact, no way depends on heat and cold; nor is it ascribed thereto by Telesius himself, nor can it be ascribed to them upon any evidence in the nature of things; seeing matter when moved from its place cannot but draw other matter to it, whether it be hot or cold, wet or dry, hard or soft, friendly or unfriendly; insomuch that a hot body will sooner attract the coldest body to its side, than suffer itself to be deserted and separated from all. For the bond of matter is stronger than the enmity of heat and cold; nor does the sequacity of matter care for the diversity of special forms. Therefore this virtue of connexion does not at all depend upon those principles of heat and cold. Next come two virtues opposed to each other, by which this kingdom of principles has been transferred (as may be thought) to heat and

cold, but on a claim of right not well made out; I mean those virtues by which beings open and rarefy, dilate and expand themselves, so as to occupy a greater space and spread themselves over a larger sphere; or contrariwise close and condense, confine and contract themselves, so as to cover less space and shrink into a smaller sphere. We must show therefore how far this virtue has its origin from heat and cold, and how far it keeps separate and unmixed with them. Now it is most true, as Telesius affirms, that density and rarity are as it were the proper work of heat and cold; for they have far the most to do in making bodies occupy a larger or less space; but yet these things are understood confusedly. For bodies seem sometimes to migrate and transfer themselves from one natural dimension to another, and that freely and as it were willingly, and with a change of form; sometimes they seem only to be forced away from their natural dimension, and their old form still remaining, to return to their usual dimension again. Now that virtue of progression into a new space is almost governed by heat and cold. But it is not so with that other virtue of restitution; since water expands itself into vapour and air, oil likewise and fat things into exhalation of flame, by the power of heat; nor (if the transmigration be perfect) do they care to return; nay the air itself also swells and is extended by heat. Whereas if the migration be only half effected, then after the heat is withdrawn it easily returns to itself; so that even in the virtue of restitution heat and cold have something to do. But things which are extended and drawn asunder not by means of heat, but by some violence, as soon as the violence ceases return most eagerly (even without any accession of cold or diminution of heat) to their former dimensions; as we see in the sucking of the glass egg, and the raising of the bellows. But this is still more evident in solid and gross bodies. For if a piece of cloth or a harp-string be stretched, on the removal of the force they rebound with great velocity; and it is the same with compression. For air compressed and imprisoned by any violence bursts out with a great force; and indeed all that mechanical motion caused by the striking of one hard body by another, commonly termed violent motion, by which solid bodies are sent flying through the air and water, is nothing but an endeavour of the parts of the discharged body to free themselves from compression; and yet here there are no apparent traces of heat

and cold. Nor can any such fine argument be made upon this doctrine of Telesius, as to say, that to every natural dimension there is assigned a quantity of heat and cold, in a certain proportion; therefore it may be that although no heat and cold are added, yet if the dimensions of the material body be extended or contracted it will come to the same thing; because more or less of matter is put in the space than is proportionate to the heat and cold. Such things, though not absurd in words, are yet the suggestions of men who are always seeking some device by which they may maintain their first thought, and do not follow out the inquiry in nature and fact. For if heat and cold be added to such extended or compressed bodies, and that in a greater measure than is proportionate to the nature of the body itself (let the stretched cloth for instance be warmed by the fire), yet it will by no means restore the balance, nor extinguish the force of restitution. I have therefore now made it plain that this virtue of dimension does not depend in any notable proportion on heat or cold; although it is this very virtue which has given most authority to these principles. Next come two virtues, which are in everybody's mouth, and are spread far and wide, namely those by which bodies are carried towards the greater masses and collections of their connaturals; in the observation whereof, as in the rest, men either trifle or go quite wrong. For the common philosophy of the school holds it enough to distinguish natural from violent motion; and to assert that heavy bodies by a natural motion are borne downwards and light bodies upwards. But such speculations are of little help to philosophy. For these words, nature, art, and violence, are but compendious phrases and trifles. They ought not only to refer this motion to nature, but likewise to seek in this very motion for the particular and proper affection and appetite of the natural body. For there are a great many other natural motions arising from very different passions of things. Therefore the thing is to be propounded according to its differences. Nay, those very motions which they call violent may be said to be more according to nature than that which they call natural; if that be more according to nature which is stronger, or even which is more according to the system of the universe. For this motion of ascent and descent is not very imperious, nor even universal; but provincial as it were, and confined to

certain regions; and it is moreover obedient and subject to other motions. And as for saying that heavy things move downwards and light upwards, it is the same as saying that heavy things are heavy and light light. For that which is predicated is assumed in the subject by the very force of the term. But if by heavy they mean dense and by light rare, they do advance somewhat; yet so as to arrive at an adjunct and concomitant rather than a cause. Those on the other hand who explain the appetites of heavy and light things by contending that the one are borne to the centre of the earth, and the other to the circumference and compass of the heaven, as to their proper places, certainly assert something, and likewise point towards a cause; but altogether wrongly. For place has no forces, nor is body acted on except by body; and all swift motion of a body, which seems as if it were seeking a place for itself, is really in pursuit not of location or position simply, but with reference to some other body.